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NAME

       expand - convert tabs to spaces

SYNOPSIS

       expand [-t tablist][file ...]

DESCRIPTION

       The  expand  utility  shall  write  files  or the standard input to the
       standard output with <tab>s replaced with one or more  <space>s  needed
       to  pad  to  the next tab stop. Any <backspace>s shall be copied to the
       output and cause the column position count for tab stop calculations to
       be  decremented;  the  column  position  count shall not be decremented
       below zero.

OPTIONS

       The expand utility shall conform to  the  Base  Definitions  volume  of
       IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.

       The following option shall be supported:

       -t  tablist
              Specify  the  tab  stops.  The application shall ensure that the
              argument tablist consists of either a  single  positive  decimal
              integer or a list of tabstops. If a single number is given, tabs
              shall be set that number of column positions  apart  instead  of
              the default 8.

       If  a  list  of tabstops is given, the application shall ensure that it
       consists of a list of two or more positive decimal integers,  separated
       by  <blank>s  or  commas,  in ascending order. The tabs shall be set at
       those specific column positions. Each tab stop N shall  be  an  integer
       value  greater  than zero, and the list is in strictly ascending order.
       This is taken to mean that, from the start of a line of output, tabbing
       to  position  N  shall  cause  the next character output to be in the (
       N+1)th column position on that line.

       In the event of expand having to process a <tab> at a  position  beyond
       the  last  of  those  specified  in a multiple tab-stop list, the <tab>
       shall be replaced by a single <space> in the output.

OPERANDS

       The following operand shall be supported:

       file   The pathname of a text file to be used as input.

STDIN

       See the INPUT FILES section.

INPUT FILES

       Input files shall be text files.

ENVIRONMENT VARIABLES

       The following environment  variables  shall  affect  the  execution  of
       expand:

       LANG   Provide  a  default value for the internationalization variables
              that are unset or null. (See  the  Base  Definitions  volume  of
              IEEE Std 1003.1-2001,    Section    8.2,    Internationalization
              Variables for the precedence of  internationalization  variables
              used to determine the values of locale categories.)

       LC_ALL If  set  to a non-empty string value, override the values of all
              the other internationalization variables.

       LC_CTYPE
              Determine the locale for  the  interpretation  of  sequences  of
              bytes  of  text  data as characters (for example, single-byte as
              opposed to multi-byte characters in arguments and input  files),
              the processing of <tab>s and <space>s, and for the determination
              of the width in column positions each character would occupy  on
              an output device.

       LC_MESSAGES
              Determine  the  locale  that should be used to affect the format
              and contents of diagnostic messages written to standard error.

       NLSPATH
              Determine the location of message catalogs for the processing of
              LC_MESSAGES .

ASYNCHRONOUS EVENTS

       Default.

STDOUT

       The  standard output shall be equivalent to the input files with <tab>s
       converted into the appropriate number of <space>s.

STDERR

       The standard error shall be used only for diagnostic messages.

OUTPUT FILES

       None.

EXTENDED DESCRIPTION

       None.

EXIT STATUS

       The following exit values shall be returned:

        0     Successful completion

       >0     An error occurred.

CONSEQUENCES OF ERRORS

       The expand utility shall terminate with an error message  and  non-zero
       exit  status  upon  encountering difficulties accessing one of the file
       operands.

       The following sections are informative.

APPLICATION USAGE

       None.

EXAMPLES

       None.

RATIONALE

       The expand utility is  useful  for  preprocessing  text  files  (before
       sorting, looking at specific columns, and so on) that contain <tab>s.

       See the Base Definitions volume of IEEE Std 1003.1-2001, Section 3.103,
       Column Position.

       The tablist option-argument consists of integers  in  ascending  order.
       Utility  Syntax  Guideline  8  mandates  that  expand  shall accept the
       integers (within the single argument) separated using either commas  or
       <blank>s.

FUTURE DIRECTIONS

       None.

SEE ALSO

       tabs , unexpand

COPYRIGHT

       Portions  of  this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
       Specifications Issue 6, Copyright (C) 2001-2003  by  the  Institute  of
       Electrical  and  Electronics  Engineers, Inc and The Open Group. In the
       event of any discrepancy between this version and the original IEEE and
       The  Open Group Standard, the original IEEE and The Open Group Standard
       is the referee document. The original Standard can be  obtained  online
       at http://www.opengroup.org/unix/online.html .